全文获取类型
收费全文 | 218篇 |
免费 | 12篇 |
专业分类
林业 | 7篇 |
农学 | 18篇 |
基础科学 | 1篇 |
72篇 | |
综合类 | 6篇 |
农作物 | 31篇 |
水产渔业 | 14篇 |
畜牧兽医 | 54篇 |
园艺 | 2篇 |
植物保护 | 25篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 13篇 |
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 9篇 |
2016年 | 7篇 |
2015年 | 15篇 |
2014年 | 9篇 |
2013年 | 11篇 |
2012年 | 13篇 |
2011年 | 20篇 |
2010年 | 13篇 |
2008年 | 18篇 |
2007年 | 15篇 |
2006年 | 10篇 |
2005年 | 8篇 |
2004年 | 9篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1973年 | 1篇 |
1971年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有230条查询结果,搜索用时 31 毫秒
161.
Evaluation of extracts and isolated fraction from Capparis spinosa L. buds as an antioxidant source 总被引:16,自引:0,他引:16
Germanò MP De Pasquale R D'Angelo V Catania S Silvari V Costa C 《Journal of agricultural and food chemistry》2002,50(5):1168-1171
The antioxidant activity of extracts from Capparis spinosa L. buds was evaluated using different in vitro tests: ascorbate/Fe(2+)-mediated lipid peroxidation of microsomes from rat liver; bleaching of 1,1-diphenyl-2-picryl-hydrazyl radical; and autoxidation of Fe(2+) ion in the presence of bathophenanthroline disulfonate. The methanolic extract showed strong activities in all of these in vitro tests. The amount of total phenols was determined in the methanolic extract. In addition, the level of rutin was calculated as 0.39% (w/w) by HPLC analysis. Our findings indicate the following: (a) the antioxidant efficiency of the methanolic extract may be attributed to its phenolic content; and (b) the antioxidant activity of the methanolic extract was maintained after removal of glucosinolates, confirming that these compounds do not interfere with the antioxidant properties of the extract. The results obtained from this study exalt the nutritional value of the flowering buds (capers) which are widely used as a source of flavor. 相似文献
162.
Comparison of black,purple, and yellow barleys 总被引:1,自引:0,他引:1
Thin?Meiw?ChooEmail author Bernard?Vigier Keh?Ming?Ho Salvatore?Ceccarelli Stefania?Grando Jerome?D.?Franckowiak 《Genetic Resources and Crop Evolution》2005,52(2):121-126
Many barley landraces are purple-or black-seeded, but the chemical composition of these purple-and black- seeded barley is rarely examined. Therefore, studies were conducted to determine if the chemical composition of purple and black barleys differs from that of yellow barleys. Four sets of genetic materials were used for these studies: 96 doubled-haploid (DH) lines, 10 near-isogenic lines, 40 landraces, and four F3 bulks. The results showed that purple DH lines contained a similar amount of lignin as yellow DH lines and that anthocyanin-containing isogenic lines did not differ from anthocyanin-free lines in lignin content. Therefore, these results suggest that anthocyanin biosynthesis is independent of lignin biosynthesis in barley. The results also showed that black barley contained more protein and more lignin than yellow barley in two crosses and that among the 40 landraces studied, the three with the highest concentration of lignin happened to be black seeded. Lignin content was not associated with seed weight except in defective endosperm lines. The presence of pigments and a relatively high concentration of lignin might help reduce the level of kernel blight severity in black barley. More studies are needed to determine the chemical composition and pest resistance associated with purple and black barleys. 相似文献
163.
Gerardo Ojeda Joana Patrício Stefania Mattana Abilio J. F. N. Sobral 《Journal of Soils and Sediments》2016,16(10):2482-2491
Purpose
Biochar is a carbon-rich product, able to enhance soil fertility and mitigate CO2 emissions. While biochar effects on agriculture are becoming known, its impact elsewhere, e.g., on estuarine ecosystems, has yet to be assessed. The main aim of the present study was to determine the effect of biochar on sediment–water retention, CO2 emissions from sedimentary organic carbon decomposition, sediment pH and electrical conductivity, in aerobic conditions similar to those observed at low tide.Materials and methods
Sediments from the Mondego Estuary (Portugal) were mixed with pine gasification biochar at different doses (5, 10, 14 %) and immersed in water with different salinity values (15, 25, 30) for 96 h. The influence of biochar on water retention, the residence time of water and CO2 emissions between ?0.75 and ?1.5 MPa, total organic carbon, pH and electrical conductivity (EC) were determined. Carbon chemical composition and polycyclic aromatic hydrocarbon (PAH) concentrations were determined in sediments and biochar. Differences between biochar treatments after immersion in different water salinities were analysed using the Kruskal–Wallis test.Results and discussion
Results showed that biochar was able to (a) increase sediment–water content in terms of quantity and residence time, (b) decrease CO2 emissions, but only with a specific soil–water content and at the highest biochar dose, (c) increase sediment pH at all biochar doses and (d) increase sediment EC at the highest biochar dose. In contrast, the percentage of carbon mineralised was not modified. Biochar carbon was rich in PAHs and less decomposable than sedimentary carbon. The increments observed in sediment pH and EC were unable to change sediment alkaline or saline status according to standard classifications.Conclusions
Our results suggest that the remarkable water adsorption capacity of biochar–sediment mixtures may be considered the main factor in regulating CO2 emission rates from sediments, together with high PAH concentrations, which probably restrain the organic matter decomposition process.164.
Variation in endosperm protein composition and technological quality properties in durum wheat 总被引:4,自引:0,他引:4
E. Porceddu T. Turchetta S. Masci R. D'Ovidio D. Lafiandra D.D. Kasarda A. Impiglia M.M. Nachit 《Euphytica》1998,100(1-3):197-205
Durum wheat quality is controlled by endosperm protein content and composition. Electrophoretic, protein content and SDS sedimentation
analyses were carried out on a large collection of accessions of durum wheat from Turkey, and compared with Italian cultivars.
A number of patterns were detected, resulting from the combination of different alleles at genomes A and B, and new allelic
variants were identified. Genotypes with the same allele at Gli-B1 showed inconsistencies in the comparison of low molecular
weight glutenin subunits (LMW-GS), suggesting caution in considering γ-gliadins as genetic markers for pasta quality. Variation
in protein content and SDS sedimentation values was wider in the Turkish material than in the Italian cultivars, the values
of which were in line with cultivars from Australia, Canada, France, and the USA. A substantial amount of the variation in
gluten properties was explained in terms of protein composition, with LMW-GS making the largest contribution. Reversed phase
high performance liquid chromatography (RP-HPLC) analyses were carried out on two biotypes of the Italian cultivar Lira that
differ at the Gli-B1/Glu-B3 loci (Lira 42 has γ-42, LMW-1, and poor quality; whereas Lira 45 has γ-45, LMW-2, and good quality).
The results indicated that differences in quality may be due to: 1) the absolute amount of LMW glutenins which was greater
in LMW-2; 2) the relative predominance of LMW-s type and LMW-m type subunits in Lira 45 glutenins which act as polymer chain
extenders; and 3) the higher proportion of the α-type and γ-type glutenin subunits, in Lira 42 glutenins, which have an additional
(nine) cysteine residue in the N-terminal region and act as glutenin chain terminators. The conclusion reached was that breeding
for quality should consider selection for LMW-GS and against α-type and γ-type glutenin subunits.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
165.
Franconi F Coinu R Carta S Urgeghe PP Ieri F Mulinacci N Romani A 《Journal of agricultural and food chemistry》2006,54(8):3121-3125
In vitro studies show that some individual minor polar phenolic compounds (MPC) present in virgin olive oil prevent oxidation of human low-density lipoproteins (LDL), but few data are available on the antioxidant effect of whole oil extract. Thus, whole virgin olive extracts were studied to determine whether they maintain the antioxidant activity and whether this last is linked to MPC composition of a single virgin oil. Using HPLC-DAD the MPC content in Taggiasca and Seggianese virgin olive oils was measured. Taggiasca oil was less rich in total MPC (208.5 mg/L) than Seggianese oil (441.9 mg/L). In addition, the major compounds of Taggiasca oil were lignan derivatives, whereas the major compounds in Seggianese oils were secoiridoid derivatives. Moreover, Taggiasca oil was practically free of 5-hydroxytyrosol and 5-hydroxytyrosol derivatives, deacetoxy-oleuropein aglycone and oleuropein aglycone. The antioxidant activity of the oils on human LDL was evaluated by measuring malondialdehyde and conjugate diene generation induced by copper ions. In both tests, the oil extracts dose-dependently reduced malondialdehyde and conjugate diene generation. Moreover, antioxidant potency correlated with total MPC; thus, Seggianese extract was more active. The two oils differed quantitatively and qualitatively, and these differences influenced their biological activities; thus clinical trials focused on studying the effects of olive oils should specify the oils used. 相似文献
166.
Stefania Galletti Eleonora Sala Onofrio Leoni Susanna Cinti Claudio Cerato 《Soil biology & biochemistry》2008,40(9):2170-2173
Biofumigation is a biocontrol method that uses volatile compounds to combat soil pathogens. We investigated a biofumigation process based on the green manure of Brassicaceae. These plants contain the glucosinolate-myrosinase system which releases inhibitory compounds such as isothiocyanate into the soil. However, the biocontrol effectiveness is often lower than expected, possibly due to microbial transformation of the isothiocyanates. In order to identify the possible function of microorganisms, their interaction with glucosinolates and glucosinolate-derived products was investigated. We report the ability of a soil isolate of Aspergillus flavus to grow in liquid culture and convert 2-propenyl and 2-phenylethyl glucosinolate and their desulfo-derivatives, to nitriles. This finding would suggest the existence of an arylsulfatase and a β-thio-glucosidase, different from myrosinase, which could direct glucosinolate conversion in soil towards nitriles rather than isothiocyanates. If confirmed in soil, our observations could at least partially explain the low concentrations of isothiocyanates after biofumigation. 相似文献
167.
Assessment of Potential Nutrient Release from Phosphate Rock and Dolostone for Application in Acid Soils 总被引:2,自引:0,他引:2
Rogrio Borguete Alves RAFAEL Mara Luisa FERNNDEZ-MARCOS Stefania COCCO Maria Letizia RUELLO David C. WEINDORF Valeria CARDELLI Giuseppe CORTI 《土壤圈》2018,28(1):44-58
Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions(0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at p H 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size,leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased,corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils. 相似文献
168.
Michael G. Stamatakis Ioanna Stefania Stamataki Spyridoula Giannatou Charalampos Vasilatos Foteini Drakou Ioannis Mitsis 《Archives of Agronomy and Soil Science》2017,63(6):735-747
In the present study, zeolite tuffs of diverse chemistry, mineralogy and origin were characterized and tested for their efficiency as slow release fertilizers (SRF) through a series of leaching tests. Mixtures of zeolite tuffs were created and tested as loamy soil additives, in order to evaluate any synergistic effect on their cation exchange capacity (CEC) and SRF properties. The studied materials were a chabazite-rich tuff (SOR), a mordenite-rich tuff (KIM), 3 mixtures of them (SOR/KIM 30/70, 50/50 and 70/30) and a commercial clinoptilolite-rich tuff (BLG). CEC (sodium acetate method) was 95.7 for BLG, 100.9 for KIM and 92.2 cmol kg?1 for SOR, while their mixtures displayed intermediate values. SRF values vary, with the SOR/KIM 30/70 exhibiting the slowest NH4+ release in 29 days (1.7%) compared to the control sample (19%). Zeolites promoted PO4?3 release, while their selectivity for Mg2+ and K+ was clearly affected by their different structure and chemistry. BLG exhibited the strongest selectivity for Mg2+, having the lowest release (39%). The results demonstrate that mixtures of zeolite tuffs could have a potential use in agricultural processes, by improving parameters like: chemistry, mineralogy, CEC and SRF efficiency, and resulting in the production of a competitive and functional soil additive. 相似文献
169.
Roberto Tamburro Stefania Pinna Anna Maria Tribuiani Alessandra Panacea Fabio Carli Antonio Venturini 《Journal of veterinary science (Suw?n-si, Korea)》2012,13(1):93-98
The purpose of this study was to evaluate a new extracapsular surgical technique for the treatment of cranial cruciate ligament rupture in small breed dogs. Nine small breed dogs (seven females and two males) weighing ≤ 15 kg were treated with biceps femoris muscle transposition (BFT). The duration of the BFT procedure was 20 min. Each patient underwent a standard clinical protocol and a questionnaire for the owners. Follow-up (at 1, 3, and 12 months postoperative) confirmed significant improvement in all patients, especially at 1 month postoperatively (p < 0.01) and again after complete stifle joint assessment at 3 months postoperatively. After 12 months, only two patients showed a slight increase in osteoarthritis. According to our results, BFT is a simple extracapsular surgical technique that can be used for the treatment of cranial cruciate ligament rupture in small breed dogs. 相似文献
170.
Cerrato S Brazis P Della Valle MF Miolo A Petrosino S Di Marzo V Puigdemont A 《Veterinary journal (London, England : 1997)》2012,191(3):377-382
Palmitoylethanolamide (PEA) is an endogenous lipid mediator with anti-inflammatory and anti-hyperalgesic properties. The main objective of the present study was to evaluate the effects of PEA on the cutaneous allergic inflammatory reaction induced by different immunological and non-immunological stimuli in hypersensitive dogs. Six spontaneously Ascaris hypersensitive Beagle dogs were challenged with intradermal injections of Ascaris suum extract, substance P and anti-canine IgE, before and after a single oral administration of PEA at doses of 3, 10 and 30 mg/kg. A significant reduction in wheal area induced by both antigen and anti-canine IgE challenge was observed after PEA administration. No significant differences were observed between the two higher doses studied, suggesting that the 10 mg/kg dose had exerted the maximum inhibitory effect. When blood levels of PEA were compared with the effects at different times, an evident correlation was obtained. However, the anti-inflammatory effects of PEA were more long-lasting than their plasma concentrations. The intradermal injection of substance P did not reveal any skin reaction (wheal or erythema formation) at any of the concentrations tested. In conclusion, PEA might constitute a new therapeutic strategy for the treatment of allergic inflammatory skin diseases in companion animals. 相似文献